#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-8;
int INF = INT_MAX / 2;

bool kaibun(string s) {
	int n = s.length();
	for (int i = 0, j = n - 1; i < j; i++, j--)
		if (s[i] != s[j])
			return false;
	return true;
}

int main() {
	string S; cin >> S;
	int n = S.length();
	int maxi = 0;
	for (int i = 0; i < n; i++)
		for (int j = i + 1; j <= n; j++)
			if (kaibun(S.substr(i, j - i)) && j - i < n)
				maxi = max(maxi, j - i);
	cout << maxi << endl;
}